Getting Started with Kogito Serverless Workflow

This guide quickly explains how to getting started with Kogito Serverless Workflows in your local machine

Prereqs

1. Java SDK installed
2. Maven installed
3. Quarkus CLI

To edit your workflows:

1. Visual Studio Code with Red Hat Java Plugin installed
2. Serverless Workflow Editor

Creating the project

To create the project skeleton, run:

quarkus create app \
  -x=kogito-quarkus-serverless-workflow \
  -x=quarkus-container-image-jib \
  -x=quarkus-resteasy-jackson \
  -x=quarkus-smallrye-openapi \
  -x=kubernetes \
 org.acme:my-first-ksw:1.0

The org.acme:my-first-ksw:1.0 is the group id, artifact id, and version of your project.

This command will create a Maven Quarkus project in the my-first-ksw directory with all required Kogito dependencies.

Next, to make sure everything is working fine, try to compile the project with:

quarkus build

Creating your first Workflow

Go to the directory src/main/resources and create a file named greetings.sw.yaml. You can play around and type the workflow definition by hand using the editor intellisense feature or copy and paste from the snnipet below:

---
id: greetings
version: '1.0'
name: Hello Person
start: InjectHello
functions:
- name: printOutput
  type: custom
  operation: sysout
states:
- name: InjectHello
  type: inject
  data:
    message: 'Hello '
  transition: PrintMessage
- name: PrintMessage
  type: operation
  actions:
  - name: print
    functionRef:
      refName: printOutput
      arguments:
        message: "${ .message + .name }"
  stateDataFilter:
    output: "${ { message: (.message + .name) } }"
  end: true

Then run quarkus dev from the project's root to start the Quarkus console.

To interact with the application, we have a couple of options described in the sections below.

Using the Swagger UI

Point your browser to the http://localhost:8080/q/swagger-ui/ address. You should see a POST endpoint definition for this workflow named Greetings. Click on the POST entry and in the button "Try it".

Copy and paste the following content:

{
  "workflowdata": {
   "name" : "John"
  }
}

Click on "Execute" and you should see a response similarly to this one:

{
  "id": "c758eb9d-6242-4bda-a5f5-7f5d302943c0",
  "workflowdata": {
    "greeting": "Hello John",
  }
}

Calling the service via command line

You can use an one line curl:

curl -X POST -H 'Content-Type:application/json' -H 'Accept:application/json' -d '{"workflowdata" : {"name": "John"}}' http://localhost:8080/greetings

Building your project's image

You can use the Quarkus CLI to build your image with the following command:

quarkus build \
  -Dquarkus.container-image.build=true \
  -Dquarkus.kubernetes.deployment-target=knative \
  -Dquarkus.container-image.group=dev.local

After building the image, you can start the container running:

docker run --rm -it -p8080:8080 dev.local/my-first-ksw:1.0

You can then interact with the application the same way you did before in the previous sections.

Deploying to Knative

Assuming you have installed Knative locally on your Minikube, run:

# Configure your docker env to push the images to the minikube registry first
eval $(minikube -p minikube docker-env --profile knative)

# rebuild the application to genereate the image in the right place
quarkus build \
  -Dquarkus.container-image.build=true \
  -Dquarkus.kubernetes.deployment-target=knative \
  -Dquarkus.container-image.group=dev.local

# Install the app!
kubectl apply -f target/kubernetes/knative.yml

# You should see something like "service.serving.knative.dev/my-first-ksw created" in the terminal

Wait a couple of seconds and run kn service list:

kn service list

NAME           URL                                              LATEST               AGE   CONDITIONS   READY   REASON
my-first-ksw   http://my-first-ksw.default.127.0.0.1.sslip.io   my-first-ksw-00001   12s   3 OK / 3     True  

Access the application as you normally would.

Tip: Run minikube tunnel -p knative to be able to access the application from your terminal. Your admin password might be asked.

Resources

• Quarkus Container Images Guide
• Getting Started With Quarkus
• CNCF Serverless Workflow
• Kogito Serverless Workflow